solar system.ppt

1、Solar System Speaker : carol,content,Star Planet and Satellite Comet Extra-terrestrial,Milky way galaxylksi,Solar system,How many planet in solar system,Mercury m:kjuri水星 Venus vi:ns金星 Earth 地球 Mars 火星 Jupiter du:pit木星 Saturn stn土星 Uranusjurns天王星 Neptune neptju:n海王星,Plutoplu:tu 冥王星,Pluto is now cons

2、idered a dwarf planet dwelling in the Kuiper belt. Neptune neptju:n海王星,origin,Many scientists think our solar system formed from a giant, rotating cloud of gas and dust known as the solar nebulanebjul . As the nebula collapsed because of its gravity, it spun faster and flattened into a disk. Most of

3、 the material was pulled toward the center to form the sun. Other particles within the disk collided and stuck together to form asteroid-sized objects named as planetesimalsplntesimls, some of which combined to become the asteroids, comets, moons and planets.,Solar System,Inner Solar System Inner Pl

4、anets:The inner four planets Mercury, Venus, Earth and Mars are made up mostly of iron and rock. They are known as terrestrialtirestril or earthlike planets because of their similar size and composition. Asteroid belt Outer Solar System Outer Planets Comets,Solar system,The solar wind from the sun w

5、as so powerful that it swept away most of the lighter elements, such as hydrogenhaidrdn and helium氦hi:lim , from the innermost planets, leaving behind mostly small, rocky worlds. The solar wind was much weaker in the outer regions, however, resulting in gas giants made up mostly of hydrogen and heli

6、um.,Sun,The sun is by far the largest object in our solar system, containing 99.8 percent of the solar systems mass. It sheds most of the heat and light that makes life possible on Earth and possibly elsewhere. Planets orbit the sun in oval-shaped paths called ellipsesilipsiz, and the sun is slightl

7、y off to the side of the center of each ellipse,Consistent of sun,Photosphere solar prominence prminns日珥 Corona krun日冕,total solar eclipse,Mercury,Venus,Earth,centrosphere sentrsfi mantle mntl earth crust,geomagnetic field,period of revolution rotation revolution,Mars,-222 to 30 Celsius selsis degre

8、e,Mars face,Age of Terasters,Asteroid belt,Asteroid belt,Asteroids are minor planets, most of which circle the sun in a region known as the asteroid belt, between the orbits of Mars and Jupiter. Scientists estimate that there are more than 750,000 asteroids in the belt with diameters larger than thr

9、ee-fifths of a mile (1 kilometer), and there are millions of smaller asteroids.,Castalia 小行星,. A number have orbits that take them closer into the solar system that sometimes lead them to collide with Earth or the other inner planets.,outer planets,The outer planets are giant worlds with thick outer

10、 layers of gas. Nearly all their mass is made up of hydrogen and helium, giving them compositions like that of the sun. Beneath these outer layers, they have no solid surfaces the pressure from their thick atmospheres liquefy their insides, although they might have rocky cores. Rings of dust, rock,

11、and ice encircle all these giants, with Saturns being the most famous.,Jupiter,Asteroid strike the Jupiter,Jupiter, the most massive planet of the solar system. It is one of the brightest objects in the night sky; It takes nearly 12 Earth years to orbit the Sun, and it rotates once about every 10 ho

12、urs, more than twice as fast as Earth; its colourful cloud bands can be seen with even a small telescope. an icy crust.,Saturn,Saturn is classified as a gas giant planet because the exterior is predominantly composed of gas and it lacks a definite surface, although it may have a solid core.21 The ro

13、tation of the planet causes it to take the shape of an oblate spheroid; that is, it is flattened at the poles and bulges at the equator,Uranus,Neptune,Trans-Neptunian Region,Astronomers had long suspected that a band of icy material known as the Kuiper belt existed past the orbit of Neptune extendin

14、g from about 30 to 55 times the distance of Earth to the sun, and from the last decade of the 20th century up to now, they have found more than a thousand of such objects. Scientists estimate the Kuiper belt is likely home to hundreds of thousands of icy bodies larger than 60 miles (100 km) wide, as

15、 well as an estimated trillion or more comets.,Well past the Kuiper belt is the Oort cloud, which theoretically extends from 5,000 to 100,000 times the distance of Earth to the sun, and is home to up to two trillion icy bodies. Past that is the very edge of the solar system, the heliospherehi:lisfi,

16、 a vast, teardrop-shaped region of space containing electrically charged particles given off by the sun. Many astronomers think that the limit of the heliosphere, known as the heliopause hi:lip:z, is about 9 billion miles (15 billion kilometers) from the sun.,Comet,Comets are often known as dirty sn

17、owballs, and consist mainly of ice and rock. When a comets orbit takes it close to the sun, some of the ice in its central nucleus turns into gas that shoots out of the comets sunlit side, which the solar wind carries outward to form into a long tail.,Short-period comets that complete their orbits in less than 200 years are thought to originate from the the disk-shaped Kuiper belt, while long-period comets that take more than 200 ye